Host on edges

NostrStreamer/Extensions.cs

@@ -1,6 +1,7 @@
 using Amazon;
 using Amazon.Runtime;
 using Amazon.S3;
+using MaxMind.GeoIP2;
 using Newtonsoft.Json;
 using Nostr.Client.Json;
 using Nostr.Client.Keys;
@@ -50,6 +51,46 @@ public static class Extensions
         return !string.IsNullOrEmpty(user.Tags) ?
             user.Tags.Split(",", StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries) : Array.Empty<string>();
     }
+
+    public static (double lat, double lon)? GetLocation(this HttpContext ctx, IGeoIP2DatabaseReader db)
+    {
+        var ip = ctx.GetRealIp();
+        var loc = db.TryCity(ip, out var city) ? city?.Location : default;
+        if ((loc?.Latitude.HasValue ?? false) && loc.Longitude.HasValue)
+        {
+            return (loc.Latitude.Value, loc.Longitude.Value);
+        }
+
+        return default;
+    }
+
+    public static string GetRealIp(this HttpContext ctx)
+    {
+        var cci = ctx.Request.Headers.TryGetValue("CF-Connecting-IP", out var xx) ? xx.ToString() : null;
+        if (!string.IsNullOrEmpty(cci))
+        {
+            return cci;
+        }
+
+        var xff = ctx.Request.Headers.TryGetValue("X-Forwarded-For", out var x) ? x.ToString() : null;
+        if (!string.IsNullOrEmpty(xff))
+        {
+            return xff.Split(",", StringSplitOptions.RemoveEmptyEntries).First();
+        }
+
+        return ctx.Connection.RemoteIpAddress!.ToString();
+    }
+
+    public static double GetDistance(double longitude, double latitude, double otherLongitude, double otherLatitude)
+    {
+        var d1 = latitude * (Math.PI / 180.0);
+        var num1 = longitude * (Math.PI / 180.0);
+        var d2 = otherLatitude * (Math.PI / 180.0);
+        var num2 = otherLongitude * (Math.PI / 180.0) - num1;
+        var d3 = Math.Pow(Math.Sin((d2 - d1) / 2.0), 2.0) + Math.Cos(d1) * Math.Cos(d2) * Math.Pow(Math.Sin(num2 / 2.0), 2.0);
+
+        return 6376500.0 * (2.0 * Math.Atan2(Math.Sqrt(d3), Math.Sqrt(1.0 - d3)));
+    }
 }
 
 public class Variant